I'm still trying to interpret the original question, the one that started this thread. I'm not sure that you CAN have a life of your own when you have kids - once you have kids, you and the kids are in it together, for better or worse. You can't have a life of your own, because everything you do affects them. Which isn't to say that you shouldn't have your own interests, or time to yourself. Everybody needs however much space it takes to not feel too claustrophobic about the other people you're sharing your life with day in, day out, 365 days a year.   But the operative word is sharing.

To me, even the language that the question is phrased in is potentially damaging - "a life of my own" suggests a desire to be rid of the responsibility for anyone else's life. It sounds ambivalent at best, maybe even a little passive-aggressive. And if one parent has already left to go have a life of his own, how scary for a child to feel that the other parent might do the same thing.

In my opinion, for what little it's worth, I would be wondering if the kid who is acting out isn't trying to tell you something or ask you for something. Then the problem would be to figure out what.

Someone made the point about choosing your battles - the one I would pick for a showdown would be getting up and getting to school. If getting her to school means being late for your job, so be it - but every minute you're late because of getting her to school is going to have to cost her BIG (loss of spending money, or phone time, or whatever it is that she likes that YOU PROVIDE that isn't necessary for her survival,) because it's costing YOU big, and you two are in this together. She doesn't have to know that you've arranged in advance to come in to work late everyday for the next week or two so you can resolve this family problem. She does have to know that she's more important to you than your job, and that if she was in trouble, you'd put her first.